205 lines
8.0 KiB
C++
205 lines
8.0 KiB
C++
// ---------------------------------------------------------------------------
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// Created by Francisco Malpartida on 7.3.2012.
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// Copyright 2011 - Under creative commons license 3.0:
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// Attribution-ShareAlike CC BY-SA
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//
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// This software is furnished "as is", without technical support, and with no
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// warranty, express or implied, as to its usefulness for any purpose.
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//
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// Thread Safe: No
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// Extendable: Yes
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//
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// @file LiquidCrystal_SR3W.h
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// This file implements a basic liquid crystal library that comes as standard
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// in the Arduino SDK but using a generic SHIFT REGISTER extension board.
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//
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// @brief
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// This is a basic implementation of the LiquidCrystal library of the
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// Arduino SDK. The original library has been reworked in such a way that
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// this class implements the all methods to command an LCD based
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// on the Hitachi HD44780 and compatible chipsets using a 3 wire latching
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// shift register. While it has been tested with a 74HC595N shift register
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// it should also work with other latching shift registers such as the MC14094
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// and the HEF4094
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//
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// This particular driver has been created as generic as possible to enable
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// users to configure and connect their LCDs using just 3 digital IOs from the
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// AVR or Arduino, and connect the LCD to the outputs of the shiftregister
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// in any configuration. The library is configured by passing the IO pins
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// that control the strobe, data and clock of the shift register and a map
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// of how the shiftregister is connected to the LCD.
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//
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//
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// +--------------------------------------------+
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// | MCU |
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// | IO1 IO2 IO3 |
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// +----+-------------+-------------+-----------+
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// | | |
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// | | |
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// +----+-------------+-------------+-----------+
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// | Strobe Data Clock |
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// | 8-bit shift/latch register | 74HC595N
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// | Qa0 Qb1 Qc2 Qd3 Qe4 Qf5 Qg6 Qh7 |
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// +----+----+----+----+----+----+----+----+----+
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// | | | | | | |
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// |11 |12 |13 |14 |6 |5 |4 (LCD pins)
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// +----+----+----+----+----+----+----+----+----+
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// | DB4 DB5 DB6 DB7 E Rw RS |
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// | LCD Module |
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//
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// NOTE: Rw is not used by the driver so it can be connected to GND.
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//
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// The functionality provided by this class and its base class is identical
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// to the original functionality of the Arduino LiquidCrystal library.
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//
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//
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// @author F. Malpartida - fmalpartida@gmail.com
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// ---------------------------------------------------------------------------
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#ifndef _LIQUIDCRYSTAL_SR3W_H_
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#define _LIQUIDCRYSTAL_SR3W_H_
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#include <inttypes.h>
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#include "LCD.h"
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#include "FastIO.h"
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class LiquidCrystal_SR3W : public LCD
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{
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public:
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/*!
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@method
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@abstract Class constructor.
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@discussion Initializes class variables and defines the IO driving the
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shift register. The constructor does not initialize the LCD.
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Default configuration:
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Shift register LCD
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QA - 0 DB4
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QB - 1 DB5
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QC - 2 DB6
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QD - 3 DB7
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QE - 4 E
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QF - 5
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QG - 6 Rs
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GND Rw
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@param strobe[in] digital IO connected to shiftregister strobe pin.
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@param data[in] digital IO connected to the shiftregister data pin.
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@param clk[in] digital IO connected to the shiftregister clock pin.
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*/
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LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe);
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// Constructor with backlight control
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LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe,
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uint8_t backlighPin, t_backlighPol pol);
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/*!
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@method
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@abstract Class constructor.
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@discussion Initializes class variables and defines the control lines of
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the LCD and the shiftregister. The constructor does not initialize the LCD.
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@param strobe[in] digital IO connected to shiftregister strobe pin.
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@param data[in] digital IO connected to shiftregister data pin.
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@param clk[in] digital IO connected to shiftregister clock pin.
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@param En[in] LCD En (Enable) pin connected to SR output pin.
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@param Rw[in] LCD Rw (Read/write) pin connected to SR output pin.
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@param Rs[in] LCD Rs (Reg Select) pin connected to SR output pin.
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@param d4[in] LCD data 4 pin map to the SR output pin.
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@param d5[in] LCD data 5 pin map to the SR output pin.
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@param d6[in] LCD data 6 pin map to the SR output pin.
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@param d7[in] LCD data 7 pin map to the SR output pin.
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*/
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LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe,
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uint8_t En, uint8_t Rw, uint8_t Rs,
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uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7 );
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// Constructor with backlight control
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LiquidCrystal_SR3W( uint8_t data, uint8_t clk, uint8_t strobe,
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uint8_t En, uint8_t Rw, uint8_t Rs,
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uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7,
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uint8_t backlighPin, t_backlighPol pol);
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/*!
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@function
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@abstract Send a particular value to the LCD.
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@discussion Sends a particular value to the LCD for writing to the LCD or
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as an LCD command.
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Users should never call this method.
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@param value[in] Value to send to the LCD.
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@param mode[in] DATA - write to the LCD CGRAM, COMMAND - write a
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command to the LCD.
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*/
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virtual void send(uint8_t value, uint8_t mode);
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/*!
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@function
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@abstract Sets the pin to control the backlight.
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@discussion Sets the pin in the device to control the backlight. This device
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doesn't support dimming backlight capability.
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@param value: pin mapped on the 74HC595N (0, .., 7) for (Qa0, .., Qh7)
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respectively.
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@param pol: polarity POSITIVE|NEGATIVE.
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*/
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void setBacklightPin ( uint8_t value, t_backlighPol pol );
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/*!
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@function
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@abstract Switch-on/off the LCD backlight.
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@discussion Switch-on/off the LCD backlight.
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The setBacklightPin has to be called before setting the backlight for
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this method to work. @see setBacklightPin.
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@param value: backlight mode (HIGH|LOW)
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*/
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void setBacklight ( uint8_t value );
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private:
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/*!
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@method
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@abstract Initializes the LCD class
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@discussion Initializes the LCD class and IO expansion module.
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*/
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int init(uint8_t data, uint8_t clk, uint8_t strobe,
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uint8_t Rs, uint8_t Rw, uint8_t En,
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uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
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/*!
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@method
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@abstract Writes an 4 bit value to the LCD.
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@discussion Writes 4 bits (the least significant) to the LCD control data lines.
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@param value[in] Value to write to the LCD
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@param more[in] Value to distinguish between command and data.
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COMMAND == command, DATA == data.
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*/
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void write4bits(uint8_t value, uint8_t mode);
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/*!
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@function
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@abstract load into the shift register a byte
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@discussion loads into the shift register a byte
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@param value[in]: value to be loaded into the shiftregister.
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*/
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void loadSR(uint8_t value);
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fio_bit _strobe; // shift register strobe pin
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fio_register _strobe_reg; // SR strobe pin MCU register
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fio_bit _data; // shift register data pin
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fio_register _data_reg; // SR data pin MCU register
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fio_bit _clk; // shift register clock pin
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fio_register _clk_reg; // SR clock pin MCU register
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uint8_t _En; // LCD expander word for enable pin
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uint8_t _Rw; // LCD expander word for R/W pin
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uint8_t _Rs; // LCD expander word for Register Select pin
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uint8_t _data_pins[4]; // LCD data lines
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uint8_t _backlightPinMask; // Backlight IO pin mask
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uint8_t _backlightStsMask; // Backlight status mask
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};
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#endif
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